"GMA," hosted by George Stephanopoulos and Robin Roberts, drew an average of 5,147,000 total viewers last week, just 13,000 more than "Today," according to early data released Monday from Nielsen. While "GMA" has beaten "Today" before now on individual days, it hasn't done so in the weekly averages since 1996.

"GMA" has been nipping at "Today's" heels for years. It's pulled even now because of a combination of factors, including the decline of NBC's prime-time lineup, which has made it more difficult to promote the morning show to a broad audience; instability in "Today's" hosting lineup (last year Ann Curry took over for Meredith Vieira); and the clever use of stunts.

Perhaps more important to the long-term trends, "GMA" was up 7% compared with the same week a year ago, while "Today" — with cohosts Matt Lauer and Ann Curry — sank 9%.

NBC conceded ABC's victory, although executives also noted that "Today" remained ahead among viewers age 25 to 54, the key demographic for news programs. ("CBS This Morning," hosted by Charlie Rose and Gayle King, remains a distant third in the ratings.)

"'Today's' 852-week winning streak had taken on a life of its own and as odd as it is to see it end, we should acknowledge just how remarkable it has been," "Today" executive producer Jim Bell wrote in a statement.

"So as we tip our caps to the team at 'Good Morning America,' we can also take a bow ourselves and recognize the work done by countless staffers for so long," Bell added. "It is not an overstatement to call it one of the most incredible achievements in television history, one that is not likely to ever happen again. "

However, last week's margin was so tiny that it could easily be erased when the final figures are released later this week.

"This is an exciting day, but we will save any celebrating for when the final numbers come in on Thursday," Tom Cibrowski, "GMA's" senior executive producer, said in a statement.

The rankings matter because the morning news shows are enormously profitable and one of the very few areas in TV where broadcast networks still maintain a big advantage over cable. By virtue of its No. 1 ranking, "Today" has been able to rake in the lion's share of ad revenue.

For 2011, "Today" logged $484 million in commercial ad time sold compared with $298 million for "GMA," according to an estimate by research firm Kantar Media. (That doesn't include the third hour of "Today" in the 10 a.m. hour, when "GMA" does not air.)

The battle between the morning shows has inspired countless articles and at least two books. The programs have jockeyed for top guest bookings and competed to spin every round of fresh ratings data. Earlier this month, the shows dueled with rival stunts, "GMA" bringing in former "Today" co-host Katie Couric as a guest anchor, while NBC countered with Sarah Palin as a guest host.

Ironically, NBC just handed Lauer a "multiyear" contract worth at least $25 million annually. Now, he might find himself in the unaccustomed role of playing catch-up with "GMA."

"At the very least it is great PR for the show and ABC," analyst Brad Adgate of Horizon Media said of "GMA's" win. "They did accomplish it more with celebrities and programming stunts than anything else. The question is whether they can sustain the lead."